Pranlukast is a cysteinyl leukotriene receptor I antagonist (LTRAs) approved for treatment of asthma in Japan since 1995. Compared to other LTRAs, such as zafilukast and montelukast, only few cases with Churg-Strauss syndrome (CSS) have been reported in association with treatment with pranlukast. We describe a 17-year-old Japanese male patient who developed CSS with a 13 month history of mild asthma receiving pranlukast for 11 months without systemic and/or inhaled corticosteroid administration prior to development of CSS. From the aspect of temporal relationship between treatment with pranlukast and development of CSS, a direct induction of CSS by pranlukast is suggested in our case.